Hydrogen peroxide(H_(2)O_(2))oxidation and reduction reactions(HPOR/HPRR)are pivotal in various innovative electrochemical energy conversion devices.A comprehensive understanding of these mechanisms is critical for ca...Hydrogen peroxide(H_(2)O_(2))oxidation and reduction reactions(HPOR/HPRR)are pivotal in various innovative electrochemical energy conversion devices.A comprehensive understanding of these mechanisms is critical for catalyst design and performance improvement in these applications.In this work,we systematically investigate the HPOR/HPRR mechanisms on low-index Pt surfaces,specifically Pt(111),Pt(100)and Pt(110),through density functional theory(DFT)calculations combined with the computational hydrogen electrode(CHE)model.For HPOR,all the low-index Pt surfaces exhibit a unified potential-determining step(PDS)involving the electrochemical oxidation of hydroperoxyl intermediates(HOO*).The binding free energy of HOO*(Δ_(GHOO*))emerges as an activity descriptor,with Pt(110)exhibiting the highest HPOR activity.The HPRR mechanism follows a chem-electrochemical(C-EC)pathway.The rate-determining step(RDS)of HPRR is either the cleavage of the HO-OH bond(chemical)or the reduction of HO(electrochemical),depending on their respective activation energies.These activation energies are functions of the HO*binding free energy,Δ_(GHO*),establishingΔ_(GHO*)as the descriptor for HPRR activity prediction.Pt(111)and Pt(100)are identified as the most active HPRR catalysts among the studied metal surfaces,although they still experience a significant overpotential.The scaling relationship betweenΔ_(GHOO*)andΔ_(GHO*)reveals a thermodynamic coupling of HPOR and HPRR,explaining their occurrence on Pt surfaces.These findings provide important insights and activity descriptors for both HPOR and HPRR,providing valuable guidance for the design of electrocatalysts in H_(2)O_(2)-related energy applications and fuel cells.展开更多
Using first-principles calculations, we studied the interaction of methanol with the Pt（100） surface based on generalized gradient approximation. We found that top sites of Pt（100） surface are the favored adsorpti...Using first-principles calculations, we studied the interaction of methanol with the Pt（100） surface based on generalized gradient approximation. We found that top sites of Pt（100） surface are the favored adsorptive positions in energy, and methanol molecule interacts with the Pt surface through oxygen atoms. Moreover, we also explored the possible dissociation pathways of methanol on the Pt surface, and suggested that the products of dissociation can be controlled by the external manipulation.展开更多
Since the 1980s,single-crystal Pt electrodes with well-defined surface structures have been deemed stable under mild electrochemical conditions(e.g.,in the potential region of electric double layers,underpotential dep...Since the 1980s,single-crystal Pt electrodes with well-defined surface structures have been deemed stable under mild electrochemical conditions(e.g.,in the potential region of electric double layers,underpotential deposition of hydrogen,or mild hydrogen evolution/OH adsorption)and have served as model electrodes for unraveling the structure-performance relation in electrocatalysis.With the advancement of in situ electrochemical microscopy/spectroscopy techniques,subtle surface restructuring under mild electrochemical conditions has been achieved in the last decade.Surface restructuring can considerably modify electrocatalytic properties by generating/destroying highly active sites,thereby interfering with the deduction of the structure-performance relation.In this review,we summarize recent progress in the restructuring of well-defined Pt(-based)electrode surfaces under mild electrochemical conditions.The importance of the meticulous structural characterization of Pt electrodes before,during,and after electrochemical measurements is demonstrated using CO adsorption/oxidation,hydrogen adsorption/evolution,and oxygen reduction as examples.The implications of present findings for correctly identifying the reaction mechanisms and kinetics of other electrocatalytic systems are also briefly discussed.展开更多
The adsorption of CH3CN and CH3NC on the Pt（lll） surface at the 1/4 monolayer （ML） coverage has been car-ried out at the level of density functional theory for understanding hydrogenation processes of nitriles. Th...The adsorption of CH3CN and CH3NC on the Pt（lll） surface at the 1/4 monolayer （ML） coverage has been car-ried out at the level of density functional theory for understanding hydrogenation processes of nitriles. The most favored ad-sorption structure for CH3 CN is the C--N bond almost parallel to the surface with the C-N bond interaction with adjacent surface Pt atoms. For CH3NC, the most stable configuration is the CH3 NC locates at the face center cubic （fcc） site with the C-atom bonded to three Pt atoms. In addition, the HCN and HNC adsorption has been computed, and the adsorption pattern is nearly similar to the CH3CN and CH3NC, respectively. The adsorbed molecules rehybridize on the surface, be-coming non-linear with a bent C-C-N or C-N-C angle. Furthermore, the binding mechanism of these molecules on the Pt（111） surface is also analyzed.展开更多
We applied periodic density-functional theory to investigate the adsorption of HCN on x Ni@Pt（111） bimetallic surfaces（x = 1~4）. The results have been compared with those obtained on pure Ni（111） and Pt（111） s...We applied periodic density-functional theory to investigate the adsorption of HCN on x Ni@Pt（111） bimetallic surfaces（x = 1~4）. The results have been compared with those obtained on pure Ni（111） and Pt（111） surfaces. For all bimetallic surfaces,HCN is preferentially tilted with the CN bond parallel to the surface,and adsorption energies increase with an increasing number of layer Ni atoms on the surface. The adsorption energies of HCN on all bimetallic surfaces are larger than that on the Pt（111） surface,whereas the adsorption energies of HCN on 3Ni@Pt（111） and 4Ni@Pt（111） are larger than that on the Ni（111） surface,indicating that the introduction of Ni to the Pt catalyst could increase the activity of bimetallic catalyst in the hydrogenation reaction for nitriles. Larger adsorption energy of HCN leads to a longer C–N bond length and a smaller CN vibrational frequency. The analysis of Bader charge and vibrational frequencies showed obvious weakening of the adsorbed C–N bond and an indication of sp2 hybridization of both carbon and nitrogen atoms.展开更多
The experimental research programs of 1950s, to understand the adsorption of CO on W surfaces, changed to ab initio studies in 2000s. The goals were to seek improved practical applications. Most of the studies were ba...The experimental research programs of 1950s, to understand the adsorption of CO on W surfaces, changed to ab initio studies in 2000s. The goals were to seek improved practical applications. Most of the studies were based on density functional theory. Many studies also used programs, such as VASP (Vienna Abinitio simulation package) and CPMD. The computational procedures used plane wave approximations. This needed studies with selection of K points and cutoff energy selection to assure convergence in energy calculations. Observations and analysis of papers published from 2006 to 2022 indicate that the cutoff energies were selected arbitrarily without any needed convergence studies. By selecting a published 2006 paper, this paper has clearly showed that an arbitrary selection of cutoff energy, such as 460 eV, is not in the range of, cutoff energies that assure convergence of energy calculations, with ab initio methods and have indicated correction procedures. .展开更多
The adsorption of thiophene on Pd(111),Pt(111),and Au(111)surfaces was investigated by periodic density functional theory(DFT)calculations at the GGA/PW91 level.The results showed that the adsorption energies of thiop...The adsorption of thiophene on Pd(111),Pt(111),and Au(111)surfaces was investigated by periodic density functional theory(DFT)calculations at the GGA/PW91 level.The results showed that the adsorption energies of thiophene on the different surfaces fol owing the order Pd(111)】Pt(111)】Au(111).The adsorption structure on the Au(111)surface showed almost no change,and the most stable adsorption structure was tilted adsorption on the top site through the S atom of thiophene.For the Pd(111)and Pt(111)surfaces,the most stable adsorption structure was paral el adsorption to the hol ow site through the ring plane of thiophene.After adsorption,the H atom of thiophene moved upward and the structure of thiophene was distorted and folded.The aromaticity of thiophene was disrupted and the C atoms were characteristic of sp3 hybridization.Furthermore,the electrons of the M(111)surfaces and thiophene were redistributed after adsorption.The electron transfer from thiophene to the M(111)surfaces was in the order Pd(111)】Pt(111)】Au(111).The electrons of the M(111)surfaces were also back-denoted to the empty orbitals of the thiophene molecule.These processes eventual y lead to the adsorption of thiophene on the M(111)surfaces.展开更多
Employing hot tungsten filament to thermal dissociate molecular hydrogen,we generated gas phase atomic hydrogen under ultra-high vacuum(UHV)conditions and investigated its interaction with Pt(111) surface.Thermal deso...Employing hot tungsten filament to thermal dissociate molecular hydrogen,we generated gas phase atomic hydrogen under ultra-high vacuum(UHV)conditions and investigated its interaction with Pt(111) surface.Thermal desorption spectroscopy(TDS)results demonstrate that adsorption of molecular hy- drogen on Pt(111)forms surface Had species whereas adsorption of atomic hydrogen forms not only surface Had species but also bulk Had species.Bulk Had species is more thermal-unstable than surface Had species on Pt(111),suggesting that bulk Had species is more energetic.This kind of weakly- adsorbed bulk Had species might be the active hydrogen species in the Pt-catalyzed hydrogenation reactions.展开更多
基金Supported by the Shanxi Province Grant(202203021212007,2023SHB003).
文摘Hydrogen peroxide(H_(2)O_(2))oxidation and reduction reactions(HPOR/HPRR)are pivotal in various innovative electrochemical energy conversion devices.A comprehensive understanding of these mechanisms is critical for catalyst design and performance improvement in these applications.In this work,we systematically investigate the HPOR/HPRR mechanisms on low-index Pt surfaces,specifically Pt(111),Pt(100)and Pt(110),through density functional theory(DFT)calculations combined with the computational hydrogen electrode(CHE)model.For HPOR,all the low-index Pt surfaces exhibit a unified potential-determining step(PDS)involving the electrochemical oxidation of hydroperoxyl intermediates(HOO*).The binding free energy of HOO*(Δ_(GHOO*))emerges as an activity descriptor,with Pt(110)exhibiting the highest HPOR activity.The HPRR mechanism follows a chem-electrochemical(C-EC)pathway.The rate-determining step(RDS)of HPRR is either the cleavage of the HO-OH bond(chemical)or the reduction of HO(electrochemical),depending on their respective activation energies.These activation energies are functions of the HO*binding free energy,Δ_(GHO*),establishingΔ_(GHO*)as the descriptor for HPRR activity prediction.Pt(111)and Pt(100)are identified as the most active HPRR catalysts among the studied metal surfaces,although they still experience a significant overpotential.The scaling relationship betweenΔ_(GHOO*)andΔ_(GHO*)reveals a thermodynamic coupling of HPOR and HPRR,explaining their occurrence on Pt surfaces.These findings provide important insights and activity descriptors for both HPOR and HPRR,providing valuable guidance for the design of electrocatalysts in H_(2)O_(2)-related energy applications and fuel cells.
文摘Using first-principles calculations, we studied the interaction of methanol with the Pt（100） surface based on generalized gradient approximation. We found that top sites of Pt（100） surface are the favored adsorptive positions in energy, and methanol molecule interacts with the Pt surface through oxygen atoms. Moreover, we also explored the possible dissociation pathways of methanol on the Pt surface, and suggested that the products of dissociation can be controlled by the external manipulation.
文摘Since the 1980s,single-crystal Pt electrodes with well-defined surface structures have been deemed stable under mild electrochemical conditions(e.g.,in the potential region of electric double layers,underpotential deposition of hydrogen,or mild hydrogen evolution/OH adsorption)and have served as model electrodes for unraveling the structure-performance relation in electrocatalysis.With the advancement of in situ electrochemical microscopy/spectroscopy techniques,subtle surface restructuring under mild electrochemical conditions has been achieved in the last decade.Surface restructuring can considerably modify electrocatalytic properties by generating/destroying highly active sites,thereby interfering with the deduction of the structure-performance relation.In this review,we summarize recent progress in the restructuring of well-defined Pt(-based)electrode surfaces under mild electrochemical conditions.The importance of the meticulous structural characterization of Pt electrodes before,during,and after electrochemical measurements is demonstrated using CO adsorption/oxidation,hydrogen adsorption/evolution,and oxygen reduction as examples.The implications of present findings for correctly identifying the reaction mechanisms and kinetics of other electrocatalytic systems are also briefly discussed.
基金Natural Science Foundation of Shanxi Province(No. 2009011014)
文摘The adsorption of CH3CN and CH3NC on the Pt（lll） surface at the 1/4 monolayer （ML） coverage has been car-ried out at the level of density functional theory for understanding hydrogenation processes of nitriles. The most favored ad-sorption structure for CH3 CN is the C--N bond almost parallel to the surface with the C-N bond interaction with adjacent surface Pt atoms. For CH3NC, the most stable configuration is the CH3 NC locates at the face center cubic （fcc） site with the C-atom bonded to three Pt atoms. In addition, the HCN and HNC adsorption has been computed, and the adsorption pattern is nearly similar to the CH3CN and CH3NC, respectively. The adsorbed molecules rehybridize on the surface, be-coming non-linear with a bent C-C-N or C-N-C angle. Furthermore, the binding mechanism of these molecules on the Pt（111） surface is also analyzed.
基金supported by the National Natural Science Foundation of China(21203027,21373048,21371034)Scientific Development Fund of Fuzhou University(2012-XQ-11)
文摘We applied periodic density-functional theory to investigate the adsorption of HCN on x Ni@Pt（111） bimetallic surfaces（x = 1~4）. The results have been compared with those obtained on pure Ni（111） and Pt（111） surfaces. For all bimetallic surfaces,HCN is preferentially tilted with the CN bond parallel to the surface,and adsorption energies increase with an increasing number of layer Ni atoms on the surface. The adsorption energies of HCN on all bimetallic surfaces are larger than that on the Pt（111） surface,whereas the adsorption energies of HCN on 3Ni@Pt（111） and 4Ni@Pt（111） are larger than that on the Ni（111） surface,indicating that the introduction of Ni to the Pt catalyst could increase the activity of bimetallic catalyst in the hydrogenation reaction for nitriles. Larger adsorption energy of HCN leads to a longer C–N bond length and a smaller CN vibrational frequency. The analysis of Bader charge and vibrational frequencies showed obvious weakening of the adsorbed C–N bond and an indication of sp2 hybridization of both carbon and nitrogen atoms.
文摘The experimental research programs of 1950s, to understand the adsorption of CO on W surfaces, changed to ab initio studies in 2000s. The goals were to seek improved practical applications. Most of the studies were based on density functional theory. Many studies also used programs, such as VASP (Vienna Abinitio simulation package) and CPMD. The computational procedures used plane wave approximations. This needed studies with selection of K points and cutoff energy selection to assure convergence in energy calculations. Observations and analysis of papers published from 2006 to 2022 indicate that the cutoff energies were selected arbitrarily without any needed convergence studies. By selecting a published 2006 paper, this paper has clearly showed that an arbitrary selection of cutoff energy, such as 460 eV, is not in the range of, cutoff energies that assure convergence of energy calculations, with ab initio methods and have indicated correction procedures. .
文摘The adsorption of thiophene on Pd(111),Pt(111),and Au(111)surfaces was investigated by periodic density functional theory(DFT)calculations at the GGA/PW91 level.The results showed that the adsorption energies of thiophene on the different surfaces fol owing the order Pd(111)】Pt(111)】Au(111).The adsorption structure on the Au(111)surface showed almost no change,and the most stable adsorption structure was tilted adsorption on the top site through the S atom of thiophene.For the Pd(111)and Pt(111)surfaces,the most stable adsorption structure was paral el adsorption to the hol ow site through the ring plane of thiophene.After adsorption,the H atom of thiophene moved upward and the structure of thiophene was distorted and folded.The aromaticity of thiophene was disrupted and the C atoms were characteristic of sp3 hybridization.Furthermore,the electrons of the M(111)surfaces and thiophene were redistributed after adsorption.The electron transfer from thiophene to the M(111)surfaces was in the order Pd(111)】Pt(111)】Au(111).The electrons of the M(111)surfaces were also back-denoted to the empty orbitals of the thiophene molecule.These processes eventual y lead to the adsorption of thiophene on the M(111)surfaces.
基金the National Natural Science Foundation of China(Grant No.20503027)Talent Program of Chinese Academy of SciencesChina Postdoc-toral Science Foundation(Grant No.2005038479)
文摘Employing hot tungsten filament to thermal dissociate molecular hydrogen,we generated gas phase atomic hydrogen under ultra-high vacuum(UHV)conditions and investigated its interaction with Pt(111) surface.Thermal desorption spectroscopy(TDS)results demonstrate that adsorption of molecular hy- drogen on Pt(111)forms surface Had species whereas adsorption of atomic hydrogen forms not only surface Had species but also bulk Had species.Bulk Had species is more thermal-unstable than surface Had species on Pt(111),suggesting that bulk Had species is more energetic.This kind of weakly- adsorbed bulk Had species might be the active hydrogen species in the Pt-catalyzed hydrogenation reactions.
